[adduxi]

Just upgraded one PC and one Laptop, both from Windows 8.1 without any issues, so far.
Took about 2 hours wait for the licenses to get activated, however they are now done. I did try initially to activate as soon as the upgrade was finished, but decided to leave them alone, and they did eventually activate on their own.
Have not tried a clean install from the ISO creation as yet, and may not either.